“I think we’re being watched” might be a suspense film cliché, but the notion of being secretly observed by some faceless adversary remains a potent element of the thriller. From the sinister figures behind the threats in conspiracy-fests like All the President’s Men, The Insider or The Constant Gardener, to the chilling videos taken within the house of the young couple in David Lynch’s Lost Highway, there’s little scarier than the thought that our every movement is being observed and used against us.

It’s exactly this paranoia that Michael Haneke relentlessly draws upon in Caché. Daniel Auteuil plays Georges, the host of an intellectual TV discussion show, who lives a privileged life with his beautiful wife Anna (Juliette Binoche) and their 12-year-old son Pierrot. One day Georges finds a videotape on his doorstep – it’s a two-hour recording of the outside of his Paris townhouse, taken the day before. As the week continues, more tapes are left, each accompanied by a childish yet gruesome drawing. Georges begins to suspect that the culprit might be a figure from his past.

Caché opens with a lengthy static shot of Georges’ house, over which the credits are printed. We presume this is an establishing shot until the footage starts to fast-forward, and it becomes clear that this is actually the first of the menacing surveillance tapes, being watched by Georges and Anne. And although Caché is ostensively a thriller, it is through genre-busting techniques like this that Haneke builds the incredible sense of unease. The traditional sources of tension are jettisoned – music, tight editing, a carefully orchestrated series of plot developments. But far from damaging the film, the sense of hyper-realistic otherworldliness makes for some of the tensest scenes you’ll experience all year. Even sequences where nothing really happens – a exhausted Georges undresses for bed, a group of students talk on the steps of a school – take on a palpable sense of dread.

The series of drawings left with the videotapes, combined with his own investigations, lead Georges to suspect that his faceless tormentor is an Algerian man called Majid. As a boy, Majid lived with Georges and his family, his parents working as farmhands until they were killed along with hundreds of other Algerians in a Parisian riot in 1961. Majid was initially adopted by Georges' parents until he was taken away into care following an incident for which Georges was at least partly responsible. It is Georges’ guilt over this event – the realisation that his actions denied Majid the privileges he had – that becomes the central focus of this film as it unfolds. Georges cannot even bring himself to tell an appalled Anne whom he thinks the culprit is, and even though Majid continues to deny making the tapes, Georges is slowly consumed by his thoughts and demons from the past. Throughout films like Funny Games, Code Unknown and The Piano Teacher, Haneke has taken a delight in tormenting the over-privileged middle classes, and although a wider knowledge of French/Algerian history is hardly necessary to enjoy the film, it does add another intriguing dimension.

Ultimately, Haneke isn’t particularly interested in answering many of the questions he sets up. There is a lengthy, much-discussed static final shot, but although it contains some potential clues to unraveling the mystery, this is hardly an M. Night Shyamalan-style twist ending; if anything, it only adds to the fog of confusion that hangs over the film. Those seeking tidy resolutions and familiar genre conventions are advised to look elsewhere, but as an exercise in bold, cerebral, nerve-jangling thrills, Caché is hard to beat.